Certain foods may pack on pounds.

Certain foods may pack on the pounds.

A new study reported in the New England Journal of Medicine by researchers from Harvard University found that certain foods pack on the pounds while other foods can actually be diet-friendly and help people lose weight when consumed regularly.

The researchers stressed that the quality of food choices, and not just calories, are key to maintaining a healthy weight.

French fries, potato chips and sweet drinks can pack on the pounds, the researchers found. Subjects who regularly consumed potato chips and other potato products, soda, and processed and unprocessed meat gained on average 3.35 pounds in four years. No surprise, especially since the portion size—and the calorie counts– of some of these foods have more than doubled in the last 30 years. These days, it is easy to buy a 20-ounce bag of chips, a 64 ounce soda, and a single-serve order of French fries which weighs in at a half a pound.

In an interesting twist, the research found that certain foods can actually help you lose weight. Yogurt, nuts, fruits, and whole grains may actually help eaters lose weight.

Eating whole grains as opposed to processed grains can make a big difference in weight loss, according to the research. Refined grains can add a half-pound every four years, while whole grains can subtract a half-pound during the same time period. Including an extra serving of nuts also prevented participants from gaining a half-pound.

While some of the findings need further explanations—why, for instance, did eating all types of potatoes (including baked potatoes) cause more weight gain than say eating sweets and desserts?!—the general take away message offers support for eating more fruits, veggies, and whole grains, and eating fewer chips and processed foods, and drinking sugar-laden soft drinks.

As a nutritionist counseling clients trying to lose weight, here is a key take home message: eating certain foods may help you lose weight and they should be included in your diet while others can pack on pounds. Making simple swaps to your diet can help you lose weight. Here are a few examples.

Skip the chips and add mixed nuts as a healthy snack.

Limit the soda and drink flavored seltzer instead.

Skip the fries and have a salad instead.

And a few other lifestyle habits which the researchers found make a difference: include regular physical activity, limit TV viewing, and be sure to get enough sleep.